Tech 21 GT2 Pops when turned OFF!

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Tech 21 GT2 Pops when turned OFF!

Postby pmkipp » 08 Sep 2017, 00:22

Any ideas how to filter this out? Works perfectly otherwise. Pop can get pretty loud. 1meg resistors from somewhere to ground? The schematic is widely available so I have attached one. Thanks.

san_amp_gt2_schematics.jpg
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Pete's Pedals
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Re: Tech 21 GT2 Pops when turned OFF! With Solution (Mostly.

Postby pmkipp » 10 Sep 2017, 13:59

This has not had many views (it is a pretty unusual problem), but just in case anyone is interested - There is a 47uf electrolytic resistor just off one leg of the switch that is NOT on the schematic. When I put a 1meg resistor from the ground of the cap to the ground on the input jack almost all of the output pop was removed. I also did the same from each of the ground terminals on the pair of 220uf power filtering caps, but that did not seem to do much more. Removing the circuit board on these is a bear, because you have to de-solder at least one jack (the Input if you want to wrestle with it) or both just to get to it. So here is a pic of what I did so you don't have to. Resistors used are all 1meg.

GT-2 Fix.jpeg
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